Wall blocks usable to form mortarless walls with set back are well known. Examples are described for example in U.S. Pat. Nos. 5,795,105; 5,490,363; 5,704,183; and, 5,711,129, the complete disclosures of each being incorporated herein by reference. In general, when it is said that a wall block is configured for forming a mortarless wall with set back, it is meant that the wall block is configured to engage other analogous blocks with set back such that mortar is not needed to secure the blocks within the wall. An example system for providing such mortarless assembly is described for example in U.S. Pat. No. 5,704,183 and comprises a locator/receiver arrangement wherein: each block includes a locator or locator arrangement thereon, typically extending upwardly from an upper surface of the block, and oriented to be engaged by a receiver, typically oriented in a side and bottom of an adjacent block, when the adjacent block is positioned “on bond.” In the system of U.S. Pat. No. 5,704,183, for example, each block includes a locator on an upper surface and a pair of insets on opposite sides which extend through the block. When a block is oriented with an identical block in half-overlap, i.e., “on bond,” the protrusion on one block will extend into one of the insets of an identical block above the first block. Interference between the locator and the inset can be used to ensure that blocks in a second course above a first course, are positioned appropriately.
It is noted that in some instances a block that is to be used in a mortarless wall, is referred to as “mortarless wall block” or by similar terms.
The present disclosure relates to providing improvements in such blocks, for desired variability in use.